The service life of a gearbox is determined by many factors. The bearings in the gearbox play a major role
since they themselves deliver an important function and in addition interact with the shafts, the casing and the
oil. Without a doubt, the sizing of the bearings is of great importance for the gearbox reliability. Since more
than 50 years the bearing dynamic carrying capacity has been used to determine a suitable size needed to
deliver a sufficient fatigue life一but despite the advanced calculation methods developed, the methods do not
fully predict service life. Producers of high quality bearing have introduced high performance class bearings
and lacking better ways to express the improved performance, this is only represented by increased dynamic
carrying capacity.